Third Point, which is known as an "activist" investment fund which now owns around 6.5 per cent of the shares in Sony, is pressing it to focus on its core activities and sell some media holdings to shareholders, according to a letter seen by the Times.
Sony told AFP that its media activities "are not for sale."
Third Point founder Daniel Loeb, known as a scrappy investor, told Sony chief executive Kazuo Hirai: "While Third Point supports your agenda for change, we also believe that to succeed, Sony must focus."
Its television and electronics business has struggled owing to problems that include slowing demand in key export markets, fierce competition from lower-cost overseas rivals, the strength of the yen, and strategic mistakes that left Sony's finances in ruins.
More From This Section
Meanwhile, Third Point has built its Sony stake quietly and is now one of the group's biggest single shareholders.
But while such action is common in the United States, it is rare for a shareholder to bring public pressure on a company in Japan, and even more so when the investor in question is based abroad.
A Sony spokesman told AFP: "As the CEO Kazuo Hirai has said several times, Sony's media activities are important for its growth and are not for sale.
"Sony is open to investments. We seek to create value for shareholders by achieving our revitalisation plan and build our electronics activities, even as we reinforce the already stable foundations in the media and financial services."
Loeb has signalled that he would accept a seat on the Sony board, the newspaper report said.